The outfile must be tab-delimited. Order of information does not matter as long as information corresponds correctly to unique name in t.txt.

Since all entries are not delimited the same, I don’t know how to start feeding these different files into different hashes with the unique names as keys. (Should I use sed on the command line to substitute single spaces with tab spaces?) After reading each file into a separate hash, the code can be this?

What's the nature of the files' entries? If they're all non-whitespace, then space and tab delimiters will be treated the same. If entires have spaces, but are delimited by tabs, that's OK, too. However, your specs are difficult for me to understand, especially w/o (redacted, if necessary) dataset samples.

A hash is a likely solution to match 'records' between the two files, but a clarification of the nature of your datasets is needed.

the three field will be fed correctly, whether the separator is one or several spaces or tabs. But provoded, of course, that there is no space within the individual fields.

Otherwise, the solution is almost certainly to read your second file and store it in a hash (with the key being the field that is common with the first file), and then tyo rerad the first file line by line and complete the content of the lines with the help of the hash. Very classical, nothing complicated, no need to preprocess the files or whatever.

Kenosis, I think I confused myself. I have removed all entries in which there was a blank, for say, name or zipcode (or any one of the categories). What I mean is that for some entries the categories are sometimes delimited by 1 space instead of a tab space.

For example,

a[tab space]b[tab space]c a b[tab space]c.

So all the information for each field is present; it's just that they (the categories) are delimited differently for some entries.

I am not sure I understood, but if you are saying that you have all the information necessary in file2.txt, then you obsiously don't need to read file1.txt and store its content in a hash. If I understood correctly, all you need to do is some form of reformating of file2.txt.

As for splitting on either space or tab, I already answered that previously.

If I understand you correctly, you want to match the files' unique name entires, and then combine some of their fields, printing them as a tab-delimited record.

If so, I'd read in t.txt first, and create a hash with each key as a unique name and the statistical number as its associated value. Then, iterate through a.txt, to match its unique name with a key, then format and print a line when found.

The script first saves the first file's name for later, then reads through t.txt, populating a hash with key/value pairs. It restores the first file's name to @ARGV and then reads through it, splitting each line and printing a record if it finds a matching unique name in the hash from a.txt.

I'm really sorry, but do you mind explaining the program again line by line? I am also trying to improve my Perl writing. I know that there are two arguments, but I thought you have to specify which argument is which file. There are also some commands, such as shift, that I don't understand.